Starting control lock by dust suppression control in mining machine

ABSTRACT

A mining machine is provided with a lock for the starting device, the lock being withdrawn by a piston and cylinder operated by a bleed from the dust suppression fluid supply, and a restriction is provided in the bleed for causing a delay in the withdrawal of the lock from the moment when the dust suppression fluid is turned on, whereby the machine cannot be started before the dust suppression fluid has been supplied to the cutting head for a period sufficient to warn away any personnel working on or in the region of the cutting head.

United States Patent [191 Perry et al.

Filed:

STARTING CONTROL LOCK BY DUST SUPPRESSION CONTROL IN MINING MACHINEInventors: Dennis Alfred Perry; John Ernest Walford, both of Lenton,England Assignee: Conflow Limited, Nottingham,

England Feb. 11, 1972 Appl. No.: 225,525

Foreign Application Priority Data Feb. 23, 1971 Great Britain 5,196/71US. Cl. 299/1, 299/12 Int. Cl. E2lc 35/04 Field of Search 299/1, 12;173/3,

References Cited UNITED STATES PATENTS 7/1912 Carnahan 173/77 11]3,743,354 [451 July 3, 1973 2,907,303 10/1959 Ritchie et a1, 173/3Primary Examiner- -Emest R. Purser L i A tiorney- Allan M. Lowe and J.Ralph King [5 7] ABSTRACT A mining machine is provided with a lock forthe starting device, the lock being withdrawn by a piston and cylinderoperated by a bleed from the dust suppression fluid supply, and arestriction is provided in the bleed for causing a delay'in thewithdrawal of the lock from the moment when the dust suppression fluidis turned on, whereby the machine cannot be started before the dustsuppression fluid has been supplied to the cutting head for a periodsufficient to warn away any personnel working on or in the region of thecutting head.

15 Claims, 7 Drawing Figures PATENTEDJuL 3 Ian 7 meet-u or 4 FIGSSTARTING CONTROL LOCK BY DUST SUPPRESSION CONTROL IN MINING MACHINE Thisinvention relates to mining machines and has for its object theprovision of means for ensuring that personnel have been warned awayfrom the cutting heads before the machines are started.

According to the present invention, a minimg machine comprises astarting device, dust suppression equipment for emitting fluid in theregion of the cutting head, a manually operated valve for stopping thedust supression fluid, a lock urged by a spring towards a position inwhich it prevents operation of the starting device, a piston andcylinder for effecting withdrawal of the lock against the urge of thespring, a bleed from the dust suppression fluid supply between the valveand the cutting head for providing pressure in the cylinder at the sideof the piston for effecting withdrawal of the lock, and a restriction inthe bleed for causing a delay in the withdrawal of the lock from themoment the dust suppression fluid valve is opened. The dust suppressionfluid may be water or foam, or any other suitable liquid.

Thus, the lock constitutes an interlock between the dust suppresionequipment and the starting device, whereby the machine cannot be startedbefore the dust suppression fluid is being supplied to the cutting head,and the delay in the withdrawal of the lock caused by the restriction inthe bleed from the fluid supply results in a delay in the starting ofthe machine until fluid has been emitted in the region of the cuttinghead for a period sufficient to warn away any personnel working on or inthe region of the cutting head.

The lock may take various forms depending upon the nature of thestartingdevice of the mining machine.

Thus, if the starting device comprises a handle movable manually betweenoff and on positions, the lock may comprise the free end of the pistonrod, which engages a projection, e.g., a step or shoulder or outwardlyspring-loaded pawl on a cam, on a shaft rotatable by the startinghandle. If the starting handle is movable from an off position in eitherdirection, to .forward" and reverse positions respectively, i.e., themachine is adapted to cut in both directions of travel, then twomutually-facing projections (steps, shoulders, or outwardlyspring-loaded pawls) are provided to ensure that the handle cannot bemoved in either direction before the dust suppression fluid is beingsupplied to the cutting head.

On the other hand, if the starting device comprises a push-buttonswitch, the lock may comprise a guard on the free end of the piston rodand preventing access to the push-button before the dust suppressionfluid is being supplied to the cutting head. Alternatively, the lock maycomprise the free end of the piston rod, which upon withdrawal actuatesa cut-out switch in series with the push-button switch, so that thepush-button switch cannot become effective before the dust suppressionfluid is being supplied to the cutting head.

The restriction in the bleed is preferably adjustable, e.g., it mayconsist of a needle valve with screw adjustment of the needle, so thatthe delay (and, consequently the duration of the period of fluidemission before the starting handle can be turned) can be adjusted tosuit the particular machine or working conditions to give the personnelreasonable time to get clear of the cutting head.

The restriction is preferably provided in a bypass round a non-returnvalve lightly spring-loaded to closed position in the direction of flowof fluid in the bleed for effecting withdrawal of the lock, so that uponclosing of the valve to stop the supply of fluid to the cutting head,the spring return of the lock towards locking position operates with theminimum of delay. 7

The bleed from the fluid supply preferably effects withdrawal of thelock through a fluid pressure transmission device in which the dustsuppression fluid is separated by a fluid transfer barrier (e.g., adiaphragm, bellows, bag, or piston) from hydraulic fluid for the lockcylinder, so that particles in the dust suppression fluid cannot reachand cause damage to the piston or cylinder. However, it is preferable toprovide a filter for the hydraulic fluid. The side of the piston notsubjected to hydraulic fluid pressure is preferably bled to anatmospheric space enclosed within a bellows, or to atmosphere through afilter, so that likewise particles in the environment cannot reach andcause damage to the piston or cylinder.

The machine is preferably also provided with an audible warning device,which likewise may be operated by a bleed from the dust suppressionfluid supply, e.g., to another fluid pressure transmission device inwhich the dust suppression water is separated from air for blowing theaudible warning device by a diaphragm, bellows, bag, or piston, i.e.,the fluid pressure transmission device acts as a fluid operated pump.

One embodiment of the invention and a couple of modifications will nowbe described, by way of example only, with reference to the accompanyingdrawings, in which FIG. 1 is a diagram showing the dust suppression andsafety equipment for a mining machine according to the invention;

FIG. 2 is a section of the delay device of FIG. 1, to a larger scale andtaken from the line II-II of FIG. 3;

FIG. 3 is a section from the line III-III of FIG. 2;

FIG. 4 is an enlarged section of the lock device of FIG. 1, taken on theline IV-IV'; and

FIGS. 5 to 7 correspond to the upper part of FIG. 4 but shows threemodifications.

In FIG. 1, a supply 1 of water for a mining machine passes througha'branch connector 2 for a hose 3 leading to a fire fighting nozzle 4incorporating its own valve, before reaching a shut-off valve 5connected to a strainer 6 at which the flow is divided. One outlet 7 ofthe strainer is connected by a hose 8 to the cooling water passages of amotor 9 for driving the mining machine and from there hoses 10 conveythe cooling water to a bank of fixed sprays 11 for effecting dustsuppression when the machine is in operation. Another outlet 12 of thestrainer is connected by a hose 13 to a manifold 14, one outlet fromwhich is connected by a hose 15 to an adjustable spray 16 with a guard17, the spray 16 being set to provide the main flow of dust suppressionwater, directed (by adjusting the attitude of the spray 16) whererequired.

The outlet 7 of thestrainer 6 also has a bleed passing through a branchconnector 18 with a relief valve 19 controlling the pressure of thebleed water in a hose 20 connected to one end of a fluid pressuretransmission device 21 having a bag 22 (or fluid transfer barrier)separating the water from hydraulic fluid (which it pressurises), theother end of the fluid pressure transmission device being connected by ahose 23 to a delay device 24, the outlet of which is connected by a hose25 to a lock device 26 controlling the starting of the mining machinemotor 9 in a manner to be described presently.

Another outlet from the manifold 14 is connected by a hose 27 to anotherfluid pressure transmission device 28 in which the dust suppressionwater is separated by a piston (or fluid operated pump) from air (whichit pressurises) for blowing an audible warning device 29 connected tothe fluid operated pump by a hose 30.

In FIGS. 2 and 3 hydraulic fluid entering the delay device 24 through aconnector 31 for the hose 23 from the fluid pressure transmission device21 is prevented having a filter 38 through which the fluid must pass inorder to reach a reducing valve 39 which sets the pressure of the fluidcommunicated to a needle valve 40 (FIG. 3) providing a restriction fordelaying the flow to another lateral passage 41 leading to the bore 32,bypassing the valve 34. The needle valve has a screwadjustable plugcarrying the needle 42 enabling the duration of the delay to be preset.The delay device 24 is primed by forcing hydraulic fluid into thechamber 37 through a check valve-43 and a filter 44.

In FIG. 4- hydraulic fluid enters the lock device 26 through a connector45 (see also FIG. 1) for the hose 25 from the delay device 24 and actson a piston 46 in a cylinder 47, against the urge of a spring 48, toeffect withdrawal of a lock 49 comprises by the free end of the pistonrod 50 from engagement with an outwardly spring-loaded pawl 51 on a cam52 on a shaft 53 rotated by the starting handle (not shown) of themining machine. The cam 52 and shaft 53 are shown in the off position,and the direction of rotation to the on position is anti-clockwise, sothat until the lock 49 is withdrawn the shaft 53 cannot be rotated tothe on position. The lock cannot be withdrawn until a sufficientpressure has built up in the cylinder 47 to move the piston 46 againstthe urge of the spring 48, and because of the restriction set bytherestrictor 40 this pressure will not build up for some little timeafter the dust suppression water sprays II and 16 have come into action,so the machine cannot'be started until after the sprays'have been inaction for some time to serve as a warning.

There being no restriction in the supply of water to the fluid pressuretransmission device 28, the audible warning device 29 will be operatedas the sprays l 1 and 16 start, thus warning any personnel not noticingthe water'sprays that the machine is liable to be started at any moment.

. Seven seconds has been found to be ample warning to anyone workingnear, the cutting head of the machine that it is about the start.However, starting of the machine is a separate manual operation (i.e.,rotation spring 48 to urge the piston 46, rod 50 and lock 49 back to theposition shown in FIG. 4) opens the valve 34, thus communicatingdirectly from the bore 32 to the chamber 35 and thence to the fluidpressure transmission device 21, as the pressure fades at the sprays 11and in the hoses 8, 10. Should the water be turned off before themachine is stopped, so that the lock 49 returns to locking positionbefore the shaft 53 is returned to the off position, rotation of theshaft will not be obstructed because the pawl 51 will depress to passthe lock and then spring out again to the position shown in FIG. 4. 1

The side of the piston 46 not subjected to fluid pressure (i.e., theside with the spring 48) is bled to atmo sphere through a filter 54, sothat particles in the environment cannot reach and cause damage to thepiston 46 and cylinder 47, just as they are likewise protected by thebag 22 of the fluid pressure transmission device 21 from particles inthe dust suppression water.

In FIG. 5 the cam 52 is provided with two mutuallyfacing outwardlyspring-loaded pawls 51A,51B for use with a starting handle (not shown)movable in one direction from an off position (as shown) to a forwardposition or in the opposite direction to a reverse position, i.e., ifthe machine is adapted to cut in both directions of travel.

In FIG. 6, a guard 55 on the free end 49 of the piston rod preventsaccess to a push-button start switch 56 until the dust suppression wateris being supplied to the cutting head of the machine, but a stop button57 remains accessible at all times.

In FIG. 7, the free end 49 of the piston rod acts through aspring-loaded push rod 58 to hold the contacts (not visible) of a switch59 open until the dust suppressionwater is being supplied to the cuttinghead of the machine, the switch 59 being in series with a push-buttonswitch (e.g., such as the switch 56 without any guard) for starting themachine, which latter switch cannot, therefore, be actuated until thecontacts of the switch 59 have been closed.

What we claim is:

l. A mining machine comprising a starting device, dust suppressionequipment for emitting fluid in the region of the cutting head, amanually operated valve for stopping the dust suppression fluid, a lockurged by a spring towards a position in which it prevents operation ofthe starting device, a piston and cylinder for effecting withdrawal ofthe lock against the urge of the spring, a bleed from the dustsuppression fluid supply between the valve and the cutting head forproviding pressure in the cylinder at the side of the piston foreffecting withdrawal of the lock, and a restriction in the bleed forcausing a delay in the withdrawal of the lock from the moment the dustsuppression fluid valve is opened.

2. A mining machine as in claim 1, wherein the starting device comprisesa handle movable manually between Off and on positions, and the lockcomprises the free end of the piston rod, which engages a projection ona shaft rotatable by the starting handle.

3. A mining machine as in claim 2, wherein the projection is anoutwardly spring-loaded pawl on a cam' on the shaft rotatable by thestarting handle.

4. A mining machine as in claim 1, wherein the starting device comprisesa starting handle movable from an of position in either direction, toforward" and reverse positions respectively, and the lock com- 3 prisesthe free end of the piston rod, which engages the mutually-facingprojections on a shaft rotatable by the starting handle.

5. A mining machine as in claim 4, wherein each projection is anoutwardly spring-loaded pawl on a cam on the shaft rotatable by thestarting handle.

6. A mining machine as in claim 1, wherein the starting device comprisesa push-button switch, and the lock comprises a guard on the free end ofthe piston rod and preventing access to the push-button before the dustsuppression fluid is being supplied to the cutting head.

7. A mining machine as in claim 1, wherein the starting device comprisesa push-button switch, and the lock comprises the free end of the pistonrod, which upon withdrawal actuates a cutout switch in series with thepush-button switch, so that the push-button switch cannot becomeeffective before the dust suppression fluid is being supplied to thecutting head.

8. A mining machine as in claim 1, wherein the restriction isadjustable.

9. Amining machine as in claim 8, wherein therestriction consists of aneedle valvewith screw adjustment of the needle.

10. A mining machine as in claim 1, wherein the restriction is providedin a by-pass round a non-return valve lightly spring-loaded to closedposition in the direction of flow of fluid in the bleed for effectingwithdrawal of the lock.

11. A mining machine as in claim 1, wherein the bleed from the dustsuppression fluid effects withdrawal of the lock through a fluidpressure transmission device in which the dust suppression fluid isseparated by a fluid transfer barrier from hydraulic fluid forthe lockcylinder.

12. A mining machine as in claim 11, wherein the side of the piston notsubjected to fluid pressure is bled to atmosphere through a filter.

13. A mining machine as in claim 1 provided'with an audible warningdevice.

14. A mining machine as in claim l3,wherein the audiblewarning device isoperated by a bleed from the dust suppression fluid supply.

15. A mining machine as in claim 14, wherein the bleed for the audiblewarning device effectsoperation of the warning device by another fluidpressure transmission device.

1. A mining machine comprising a starting device, dust suppressionequipment for emitting fluid in the region of the cutting head, amanually operated valve for stopping the dust suppression fluid, a lockurged by a spring towards a position in which it prevents operation ofthe starting device, a piston and cylinder for effecting withdrawal ofthe lock against the urge of the spring, a bleed from the dustsuppression fluid supply between the valve and the cutting head forproviding pressure in the cylinder at the side of the piston foreffecting withdrawal of the lock, and a restriction in the bleed forcausing a delay in the withdrawal of the lock from the moment the dustsuppression fluid valve is opened.
 2. A mining machine as in claim 1,wherein the starting device comprises a handle movable manually between''''off'''' and ''''on'''' positions, and the lock comprises the freeend of the piston rod, which engages a projection on a shaft rotatableby the starting handle.
 3. A mining machine as in claim 2, wherein theprojection is an outwardly spring-loaded pawl on a cam on the shaftrotatable by the starting handle.
 4. A mining machine as in claim 1,wherein the starting device comprises a starting handle movable from an''''off'''' position in either direction, to ''''forward'''' and''''reverse'''' positions respectively, and the lock comprises the freeend of the piston rod, which engages the mutually-facing projections ona shaft rotatable by the starting handle.
 5. A mining machine as inclaim 4, wherein each projection is an outwardly spring-loaded pawl on acam on the shaft rotatable by the starting handle.
 6. A mining machineas in claim 1, wherein the starting device comprises a push-buttonswitch, and the lock comprises a guard on the free end of the piston rodand preventing access to the push-button before the dust suppressionfluid is being supplied to the cutting head.
 7. A mining machine as inclaim 1, wherein the starting device comprises a push-button switch, andthe lock comprises the free end of the piston rod, which upon withdrawalactuates a cut-out switch in series with the push-button switch, so thatthe push-button switch cannot become effective before the dustsuppression fluid is being supplied to the cutting head.
 8. A miningmachine as in claim 1, wherein the restriction is adjustable.
 9. Amining machine as in claim 8, wherein the restriction consists of aneedle valve with screw adjUstment of the needle.
 10. A mining machineas in claim 1, wherein the restriction is provided in a by-pass round anon-return valve lightly spring-loaded to closed position in thedirection of flow of fluid in the bleed for effecting withdrawal of thelock.
 11. A mining machine as in claim 1, wherein the bleed from thedust suppression fluid effects withdrawal of the lock through a fluidpressure transmission device in which the dust suppression fluid isseparated by a ''''fluid transfer barrier'''' from hydraulic fluid forthe lock cylinder.
 12. A mining machine as in claim 11, wherein the sideof the piston not subjected to fluid pressure is bled to atmospherethrough a filter.
 13. A mining machine as in claim 1 provided with anaudible warning device.
 14. A mining machine as in claim 13, wherein theaudible warning device is operated by a bleed from the dust suppressionfluid supply.
 15. A mining machine as in claim 14, wherein the bleed forthe audible warning device effects operation of the warning device byanother fluid pressure transmission device.